Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • A convex lens of refractive index  and focal length <img alt="18" src="https://entrancecorner.oncodecogs.com/gif

A convex lens of refractive index 1.5 and focal length 18 cm in air is immersed in water. The change in focal length of the lens will be ________ cm
(Given refractive index of water =\frac{4}{3})

Option: 1

54


Option: 2

-


Option: 3

-


Option: 4

-


Answers (1)

best_answer

\begin{aligned} & \frac{1}{\mathrm{f}}=(\mu-1)\left(\frac{1}{\mathrm{R}_1}-\frac{1}{\mathrm{R}_2}\right) \\ & \frac{1}{18}=(1.5-1) \frac{2}{\mathrm{R}} \ldots(1) \\ & \frac{1}{\mathrm{f}}=\left(\frac{1.5}{\frac{4}{3}}-1\right) \frac{2}{\mathrm{R}} \ldots . .(2) \end{aligned}
Div eq.1 by eq. 2

\begin{aligned} & \frac{\mathrm{f}}{18}=\frac{0.5 \times 8}{1} \\ & \mathrm{f}=72 \mathrm{~cm} \\ \end{aligned}

\begin{aligned} & \text { change }=72-18 \\ & =54 \end{aligned}
 

Posted by

avinash.dongre

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2025: BTech ECE cut-offs for female candidates go up at top NITs
anam-khan

JEE Main 2025 Session 2 City Slip (OUT) Live: Admit card likely on March 29 at jeemain.nta.nic.in; cut-offs
anam-khan

AESL expands Aakash Digital 2.0 to offer AI-powered coaching for NEET, JEE, Olympiads

Latest Question